Rails 3 engines testing

Hi all,

I was wondering how you can test Rails 3 engines.

Looks like the rake test task is not available by default. So I added
the following in my rake task

require 'rake/testtask'

Rake::TestTask.new do |test|
  test.pattern = 'test/**/*_test.rb'
  test.libs << 'test'
end

In my test_helper.rb file, I added:

ENV["RAILS_ENV"] = "test"

require 'rubygems'
require 'test/unit'
require 'active_support'

But still no go. If I want to run the test, I get some error messages
about a namespace I'm using (everything else is still running smoothly).

So how do you integrate the default rails testing framework from
ActiveSupport into your Rails 3 Engines?

Thank you in advance